FIRE: A Facility Class Near-Infrared Echelle Spectrometer for the Magellan Telescopes

We describe the design, construction, and commissioning of FIRE, a 0.82–2.51 μ m echelle spectrograph for the 6.5 m Magellan Baade telescope. FIRE may be operated in two modes. Its primary mode is a prism cross-dispersed echelle, which delivers R = 6000 spectra for an 0.6'' slit, with continuous wavelength coverage over the full instrument bandpass in a single setup. Alternatively, the echelle grating may be replaced with a flat mirror to obtain high-throughput R = 400 longslit spectra through the prisms alone—again with full Y/J/H/K coverage. This contribution outlines the details of the optical design and execution, mechanical and thermal design, detector systems, and data analysis software. We also present performance metrics from commissioning observations. These have established that the instrument is achieving its design goals, particularly with regard to throughput, as is required for observations of faint, high-redshift QSOs and the lowest mass brown dwarfs.